Surfactant composition and liquid detergent formulations containing same

ABSTRACT

Surfactant compositions comprising from 25 to 75 percent by weight of alkyl vicinal alkyl ether sulfates having the formula: WHERE X AND Y ARE INTEGERS FROM 0 TO 15, THE SUM OF X+ Y BEING FROM 13 TO 15, R is an alkyl group containing from one to eight carbon atoms, and M is an alkali metal or ammonium and, correspondingly from 75 to 25 percent by weight of a linear alkylbenzene sulfonate when utilized in liquid detergent formulations provide improved performance as composed to either ingredient of the surfactant composition when used alone in a comparable formulation.

United States Patent Casey et al.

[ Feb. 1,1972

l54l SURFACTANT COMPOSITION AND LIQUID DETERGENT FORMULATIONS CONTAINING SAME [72] Inventors: Edward A. Casey, St. Louis; James M.

Huggins, St. Ann, both of Mo.

[52] US. Cl 252/532, 27 21 45.!

[5|] InLCl. ..Clld l/38,C1ldl/l2 [58] Field of Search "252/138, 161', 260/458 [56] References Cited UNITED STATES PATENTS 2,09l,956 9/1937 Benner..............................260/458X 3,320,174 5/1967 Rubinfeld ..252/138 3,409,657 1 1/1968 Blood et al ..260/458 Primary Examiner-Leon D. Rosdol Assistant Examiner-P. E. Willis AnorneyHerbert B. Roberts, Roger R. Jones, Thomas N. Wallin and Neal E. Willis [57] ABSTRACT Surfactant compositions comprising from 25 to 75% by "fr e ia! me l eltylsth sgvl i seh e ferm l 0503M OR alkylbenzene sulfonatetwhen utilized in liquid detergent "V formulations provide improved performance as compared to either ingredient of the surfactant composition when used alone in a wmp re amflat m v.

9 Claims, No Drawings SURFACTANT COMPOSITION AND LIQUID DETERGENT FORMULATIONS CONTAINING SAME BACKGROUND OF THE INVENTION This invention relates to surfactant compositions and to liquid detergent formulations containing such surfactant compositions.

As is well known to those skilled in the art of formulating and marketing liquid detergent formulations, particularly those intended for use in hand dishwashing, it is desirable that such formulations provide a relatively high level of suds or foam during use in aqueous solutions. It, is conventional practice, for example, to rate the performance of a liquid dishwashing formulation based on the number of dishes which can be washed with the formulation before collapse of foam or suds in the dishpan is observed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide novel surfactant compositions particularly suited for use in liquid detergent formulations and novel liquid detergent formulations characterized by improved performance.

Basically, the subject invention resides in surfactant compositions comprisinga mixture of alkyl vicinal alkyl ether sulfates and linear alkylbenzene sulfonates as hereinafter described and in liquid detergent formulations containing such compositions as a surfactant component. The invention will be better understood from the following description of the preferred embodiments.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The surfactant compositions of this invention comprise two ingredients.

One essential ingredient is an alkyl vicinal alkyl ether sulfate having the formula:

wherein x and y are each integers from to IS, the sum of x L-y being from l3 to 15, R is an alkyl group containing one to eight carbon atomsa methyl or ethyl, particularly methyl, group being preferred, and M is an alkali metal or ammonium. The use of such compounds wherein the alkyl chain contains 16 carbon atoms (the sum of x and y is I4) is particularly preferred. Compositions comprising single alkyl chain homologs or a mixture of homologs having the required average chain length can be utilized.

It will be apparent that the compounds as defined by the foregoing formula, can exist in a variety of isomeric forms. For example, when the alkyl chain contains l6 carbon atoms, the methyl ether and sulfate groups can occupy the 1,2; 2,3; 3,4; 4,5; 6,7; or 7,8 positions. Any of such position isomers or mixtures thereof are suitable for use in this invention. It will further be understood that although this ingredient consists predominantly of compounds wherein the alkyl chain, to which the-080 M and R groups are attached, contains to 17 carbon atoms or mixtures of such homologs, minor amounts of higher and lower homologs will generally be present.

Compounds of the above type can be prepared by techniques well known to those skilled in the art. For example, the compounds can be conveniently prepared by reaction of an alkyl epoxide with methanol inthe presence of a Lewis acid catalyst followed by reaction of the Bhydroxy monomethyl ether with sulfur trioxidefollowed by neutralization with an alkali metal hydroxide of ammonia.

The second ingredient of the surfactant compositions of this invention is a linear alkylbenzene sulfonate of the type commonly employed in a variety of detergent compositions. Alkylbenzene sulfonates wherein the alkyl group contains from l0 to 14 carbon atoms are generally preferred for optimum detergency and solubility characteristics. If desired, higher alkylbenzene sulfonates can be employed, but their solubility characteristics may require the use of an emulsion stabilizer in liquid detergent formulations in which they are employed.

The surfactant compositions of this invention will contain from 25 to 75 percent by weight of the alkyl vicinal alkyl ether sulfate and, correspondingly, from 75 to 25 percent by weight of the linear alkylbenzene sulfonate. The use of these proportions provides a synergistic effect hereinafter discussed which is not significantly apparent at other concentrations.

To provide liquid detergent formulations of improved performance, from 2 to 50 percent by weight of the surfactant compositions described above are dissolved or suspended in an aqueous medium.

If desired, the liquid detergent formulation may comprise only the surfactant component and the aqueous carrier. However, alkaline builders, such as alkali metal polyphosphates; soil suspending agents such as the lower alkyl cellulose ethers, hydroxy alkyl cellulose ether, carboxy lower alkyl cellulose compounds, polymeric materials such as polyvinyl pyrrolidione, polyvinyl alcohol, hydrolyzed polyvinyl acetate, polyacrylic acid, polyacrylamide, maleic anhydride copolymers with alkyl vinyl ethers or lower alkyl groups and natural products such as starch; corrosion inhibitors; sequestrants such as ethylene diamine tetra-acetic acid; foam stabilizers such as the higher fatty acid alkylolamidesmonoethanol amide, diethanol amides, monoisopropanol amides having from about 10 to about 14 carbon atoms in the acyl moiety being particularly preferred; brighteners such as the coumerine, triazolyl stilbene and stilbene cyanuric types; tarnish inhibitors; germicides; coloring materials; perfumes; thickening agents and the like may desirably be included in the detergent fonnulations of this invention. In accordance with common practice, alcohols such as ethanol, propanol and isopropanol can be employed to improve'compatibility of the various components.

The invention is further illustrated by the following examples.

EXAMPLE I A liquid detergent formulation is prepared by admixing l5 percent by weight sodium salt of hexadecyl vicinal methyl ether sulfate; 15 percent sodium alkylbenzene sulfonate (alkyl chain length 10-13 carbon atoms); 5 percent-diethanol amide foam stabilizer; and 65 percent water. In a dishwashing test, a solution of this composition in water is used to wash plates uniformly soiled with household cooking grease. The number of plates washedbefore collapse of foam in the dishpan is observed at from 7 to l5 percent greater than the number of plates washed with comparable formulations each containing 30 percent of the individual surfactants (hexadecyl vicinal methyl ether sulfate and sodium alkylbenzene sulfonate respectively) rather than the mixed surfactant composition of this invention.

EXAMPLE II A liquid detergent formulation is prepared by admixing 22- percent by weight hexadecyl vicinal methyl ether sulfate (sodium salt; 8 percent sodium alkylbenzene sulfonate (alkyl chain lengths of l0-l3 carbon atoms); 5 percent diethanolamide film stabilizer; 65 percent water. Improvements comparable to those reported in example I are obtained in plate washing tests as compared to similar formulations containing only the individual surfactants.

EXAMPLE III A liquid detergent formulation is prepared by admixing 8 percent by weight hexadecyl vicinal methyl ether sulfate (sodium salt); 22 percent by weight sodium alkylbenzene sulfonate (alkyl chain length of 10-13 carbon atoms); 5 diethanolamide foam stabilizers; 65 percent water. Results comparable to those of example I and ll are obtained in plate washing tests.

EXAMPLE lV EXAMPLE V The procedure of example I is repeated with the exception that a potassium saltof heptadecyl vicinal methyl ether sulfate is substituted for the sodium salt of hexadecyl vicinal methyl ether sulfate. Comparable results are obtained in plate washing tests. v I

The foregoing examples clearly demonstrate that detergent fonnulations containing the surfactant compositions of this invention provide synergistic performance as compared to similar formulations containing the individual ingredients of the surfactant compositions.

What is claimed is:

l. A surfactant composition for use in liquid detergent formulations said composition consisting essentially of from 25 to 75 percent by weight of alkyl vicinal alkyl ether sulfate having the formula: v

wherein x and y are each integers from to 15, the sum of x-l-y being from 13 to l5, R is an alkyl group containing from one to eight carbon atoms, and M is selected from the group consisting of alkali metalsand ammonium and, correspondingly, from 75 to 25 percent by weight of a linear alkylbenzene sulfonate surfactant wherein a predominant proportion of the alkyl group contain from to 14 carbon atoms.

2. The composition of claim 1 where R is methyl.

3. The composition of claim 2 wherein the sum of x-t-y is 14 and said linear alkylbenzene sulfonate is a sodium alkylbenzene sulfonate in which a predominant proportion of th alkyl groups contain from 10 to l3 carbon atoms.

4. The composition of claim 2 wherein said composition comprises from 40 to 60 percent by weight of said alkyl vicinal methyl ether sulfate and, correspondingly, from 60 to 40 percent of said linear alkylbenzene sulfonate.

5. A liquid detergent formulation consisting essentially of an aqueous medium containing from 2 to 50 percent by weight, basedon the total weight of said formulation of a surfactant component consisting essentially .of from 25 to 75 percent by weight, based on the weight of said surfactant component of an alkyl vicinal alkyl ether sulfate having the formula:

wherein x and y are each integers from 0 to 15, the sum of x-l-y being from 13 to 15, R is an alkyl group containing from one to eight carbon atoms, and M is selected from the group consisting of alkali metals and ammonium and, correspondingly, from 75 to 25 percent by weight of linear alkylbenzene sulfonate surfactant wherein a predominant proportion of the alkyl group contain from l0 to 14 carbon atoms.

6. A formulation according to claim 5 wherein R is methyl.

7. A formulation according to claim 6 wherein the sum of x+y is 14 and said linear alkylbenzene is a sodium alkylbenzene sulfonate in which a predominant proportion of the alkg'llgroups contain from 1 0 to 13 carbon atoms formulation according to claim 6 wherein said surfac- 

2. The composition of claim 1 where R is methyl.
 3. The composition of claim 2 wherein the sum of x+y is 14 and said linear alkylbenzene sulfonate is a sodium alkylbenzene sulfonate in which a predominant proportion of the alkyl groups contain from 10 to 13 carbon atoms.
 4. The composition of claim 2 wherein said composition comprises from 40 to 60 percent by weight of said alkyl vicinal methyl ether sulfate and, correspondingly, from 60 to 40 percent of said linear alkylbenzene sulfonate.
 5. A liquid detergent formulation consisting essentially of an aqueous medium containing from 2 to 50 percent by weight, based on the total weight of said formulation of a surfactant component consisting essentially of from 25 to 75 percent by weight, based on the weight of said surfactant component of an alkyl vicinal alkyl ether sulfate having the formula: wherein x and y are each integers from 0 to 15, the sum of x+y being from 13 to 15, R is an alkyl group containing from one to eight carbon atoms, and M is selected from the group consisting of alkali metals and ammonium and, correspondingly, from 75 to 25 percent by weight of linear alkylbenzene sulfonate surfactant wherein a predominant proportion of the alkyl group contain from 10 to 14 carbon atoms.
 6. A formulation according to claim 5 wherein R is methyl.
 7. A formulation according to claim 6 wherein the sum of x+y is 14 and said linear alkylbenzene is a soDium alkylbenzene sulfonate in which a predominant proportion of the alkyl groups contain from 10 to 13 carbon atoms.
 8. A formulation according to claim 6 wherein said surfactant component contains from 40 to 60 percent by weight of said alkyl vicinal methyl ether sulfate and, correspondingly, from 60 to 40 percent of said linear alkylbenzene sulfonate.
 9. A formulation according to claim 6 additionally comprising from 1 to 10 percent by weight, based on the total weight of said formulation, of a higher fatty acid alkylolamide foam stabilizer. 